The Value Of Magnetic Resonance Sialography For Evaluate The Salivary Function In Nasopharyngeal Carcinoma Patients

Objective To evaluate the feasibility of Magnetic Resonance sialography（MRS）and the function changes of salivary glands following radiotherapy（RT）.Methods Nasopharyngeal carcinoma patients who conformed to the inclusion criteria were enrolled.MRS images of the salivary glands were collected at both resting and stimulating states before and after RT.The visibility of the salivary ducts,as well as the degree of subjective acute xerostomia of the patients were scored by scoring systems.Spearman rank correlation was used to test correlation between the two groups.Results 32 patients were enrolled in.Both the visibility and MRS scores of the salivary ducts were decreased after RT when compared with what they were before RT.T test showed that the absolute value of MRS score difference of the parotid glands before and after acid stimulation（DPS）between the server and non-severe acute xerostomia group were statistically significant after RT（P=0.009）,as well as the submandibular glands（DSS）between the two groups（P = 0.005）.No statistically significant were found between the two groups of the Resting Parotid duct Score（RPS）,the Stimulating Parotid duct Score（SPS）,the Resting Submandibular duct Score（RSS）and the Stimulating Submandibular duct Score（SSS）.The degree of acute xerostomia correlated with DPS（rs:-0.472,P=0.006）and DSS（rs:-0.482,P=0.005）after RT.Conclusions The results of our study implied that that MRS allowed a non-invasive way to evaluate salivary ductal changes.Objective To evaluate radiation-induced acute xerostomia and the dosimetric factor changes of the parotid and submandibular glands.Methods 109 nasopharyngeal carcinoma（NPC）patients who underwent IMRT were included.They were divided into two groups according to the severity of xerostomia: the severe and non-severe group.Several clinical factors including age,chemotherapy etc.were analyzed by chi square test.The delivered doses as well as the volumes of the parotid and submandibular were also collected,t test was used to compare the differences between the two groups.The dosimetric factors(V₁₅-V₅₀)of the parotid glands were analyzed by Binary Logistic regression（Forward-conditional method）.Results The incidence of severe acute xerostomia was 47.7%（52/109）,several clinical factors including age,mucositis and chemotherapy were analyzed,but all shown unrelated with severe acute xerostomia.Logistic regression of the parotid gland showed that V₃₄ was a independent indicating factor of severe acute xerostomia.When using V₃₄=49% as a cut-off to predict severe xerostomia,the sensitivity and specificity were 71.2% and 75.4%.Conclusions The study evaluated the delivered doses of the parotid and submandibular glands and their relationship with acute xerostomia.V₃₄ was a valuable indicator for predicting severe acute xerostomia.